1. Field of the Invention
The present invention relates to a disk cartridge to accommodate a storage disk such as an optical disk, magnetic disk or magneto-optical disk. The present invention also relates to a disk apparatus for writing data to or reading data from a storage disk.
2. Description of the Related Art
Conventionally, several kinds of storage disks, such as optical disks, magnetic disks or magneto-optical disks, have been used for storing a large amount of data. For protective purposes, a storage disk may be accommodated in a plastic cartridge. This cartridge, with the storage disk incorporated, is inserted into a disk apparatus for reading or writing data.
As is known in the art, a storage disk may be unduly charged within the plastic cartridge. The static electricity will attract dust or other small objects floating in the air. As a result, accumulations of these particles may be built up on the storage disk, which is disadvantageous to conducting proper data reading or data writing by a laser beam.
As a way to address the above problem, JP-A-7(1995)-153171 discloses a discharge brush disposed inside of the disk cartridge. This brush is brought into contact with the storage disk when the disk cartridge is inserted into the disk apparatus. Another example is disclosed in JP-A-4(1992)-134776, which teaches that a movable conductive cloth or other material is arranged between the disk cartridge and the disk apparatus for eliminating charged electricity.
While the above conventional techniques are functional, they also suffer the following drawbacks.
Specifically, the conventional discharge brush mentioned above is held in contact with the storage disk while this disk is being rotated. Likewise, the conductive cloth as the second example is brought into pressing contact with the storage disk when the rotating disk is about to be stopped. As a result, in both cases, the disk surface may be scratched or even damaged to an unacceptable extent.
Such scratches or damages in the disk surface are undesirable since they may perturb the data-reading or data-writing laser beam irradiated onto the storage disk, thereby impeding the proper data handling operations. The adverse effect will become more conspicuous when the laser beam is made smaller in diameter and therefore more susceptible to such imperfections on the disk.